Numerical modelling of high-speed diesel engines for small craft energy efficiency prediction

Manufacturers of marine high-speed diesel engines usually give only fuel consumption values corresponding to the ideal propeller curve or even just at the Maximum Continuous Rating (MCR) of the engine. Unfortunately, this simple kind of information does not allow a proper optimization of the energy savings onboard, as well as a reliable energy efficiency prediction of the whole propulsion system, including diesel generators performance. This paper presents a numerical methodology to derive fuel consumption values in the entire working area of any diesel engine, starting from very few input data. Several coefficients appear in the main mathematical equation, whose numerical values are obtained through statistical regressions derived from fuel consumption maps of some main propulsion engines and diesel generators. The proposed numerical method is tuned and tested on some high-speed diesel engines, whose loads diagrams were kindly provided by manufacturers in order to estimate the accuracy level of this kind of approach.